Low-color ultraviolet absorber compounds and compositions thereof

ABSTRACT

Novel ultraviolet absorbing compounds that are liquid in nature, are extremely low in color (and thus permit use without the concomitant necessity of adding large amounts of other coloring agents to combat such discoloring), and are highly effective in providing protection in wavelength ranges for which previous attempts at low-color ultraviolet absorbers have failed are provided herein. Such compounds provide such excellent, inexpensive, and beneficial protection from ultraviolet exposure within various media, including, but not limited to, clear thermoplastics. The particular compounds are generally polymeric in nature including various chain lengths of polyoxyalkylenes thereon and are liquid in nature to facilitate handling and introduction within the target media. In addition, such ultraviolet absorbers also exhibit extremely low migratory properties thereby providing long-term protective benefits to the target media as well. This invention also concerns the end products, specific broadly defined types of compounds providing such beneficial characteristics, methods of making such low-color compounds, and methods of producing such clear, UV protected end products.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of patent application Ser. No.09/934,376, which was filed on Aug. 21, 2001, and then granted as U.S.Patent No. 6,559,216. The parent application is herein entirelyincorporated by reference.

FIELD OF THE INVENTION

This invention relates to novel ultraviolet absorbing compounds that areliquid in nature, are extremely low in color (and thus permit usewithout the concomitant necessity of adding large amounts of othercoloring agents to combat any discoloring within clear, colorlessapplications), and are highly effective in providing protection inwavelength ranges for which previous attempts at low-color ultravioletabsorbers have failed. Such compounds provide such excellent,inexpensive, and beneficial protection from ultraviolet exposure withinvarious media, including, but not limited to, clear thermoplastics. Theparticular compounds are generally polymeric in nature including variouschain lengths of polyoxyalkylenes thereon and are liquid in nature tofacilitate handling and introduction within the target media. Inaddition, such ultraviolet absorbers also exhibit extremely lowmigratory properties thereby providing long-term protective benefits tothe target media as well. This invention also concerns the end products,specific broadly defined types of compounds providing such beneficialcharacteristics, methods of making such low-color compounds, and methodsof producing such clear, UV protected end products.

BACKGROUND OF THE PRIOR ART

All of the U.S. patents cited throughout this specification are herebyentirely incorporated herein.

Ultraviolet absorber compounds have been utilized for a number ofprotective applications, including within compositions for coveringskin, on and within apparel and other types of textiles, withintransparent plastic containers, and the like, to combat the harmful anddegradable effects of certain wavelengths of light in the UV spectrum.The best known UV absorbers are benzotriazoles, available from Cibaunder the tradename Tinuvin®, and benzophenones, available from CytecIndustries under the trademark Cyasorb™. Such compounds are highlyeffective in their UV absorber capacity; however, they are quite costly,can prove difficult to incorporate within different target media, andtend to migrate from within certain types of media (such as plastics).Furthermore, these two well known types of UV absorbers present handlingdifficulties in that they are generally produced and utilized in powderform and have relatively low melting points. Particularly, withinplastic media, the powder form of these compounds is problematic; aliquid is much easier to handle, does not require melting, and providesmore effective and thorough mixing throughout the target plastic.Additionally, these previously utilized UV absorbers provide UVprotection over a relatively narrow range of wavelengths ({circle around(2)}_(max) from about 290 to about 340 nm for benzotriazoles; from 260to 300 nm for benzophenones), which ultimately leaves a potentiallydamaging range of unprotected UV exposure (to about 400 nm). Attempts toincrease the amount of such UV absorber compounds in order to providepotential protection over such a broader wavelength range isineffective, not to mention such greater amounts of UV absorbersincreases the production of unwanted colorations within target clearplastics and other like applications such that masking compounds (e.g.,bluing agents, for example) must be utilized in relatively high amountsto combat the discoloring effect. Thus, there exists a need to provide ahighly effective, liquid ultraviolet absorber which exhibits aversatility to be incorporated within or applied to different andvarious media and substrates and which, alternatively, can provideprotection over the range of wavelengths in the UV spectrum of fromabout 290 to about 400 nm (in order to provide the best overallprotection from possible harm and/or degradation associated with UVexposure).

Methine-based compounds, in particular certain malonate derivatives, asin European Patent Abstract 350-386-A, to L'Oreal SA, are useful as UVabsorbers in cosmetic sunscreen compositions, are generally inexpensiveto make, and provide UV protection in the spectrum from about 280 toabout 360 nm. However, such compounds are highly soluble in organicsolvents and would therefore easily migrate from solid compositions,such as plastics, upon introduction therein. Thus, although theutilization of an effective UV absorber, such as a malonate derivative,within plastics, may be highly desirable, such has never been taught norfairly suggested within the prior UV absorber art due to the greatdifficulty in producing such a stable, and thus highly effective, UVabsorbing composition from such a methine-based source. There exists aneed then to produce an inexpensive UV absorber which exhibits therequisite ability to remain within media such as thermoplastics and thelike (as noted above), and thus provide necessary and desirableprotection from degradation due to UV exposure.

Further developments for the ultraviolet protection of certain polymericmedia (such as polyesters) have included methine-based compounds which,to be effective in terms of low extraction from such a thermoplastic,must be introduced during the actual polymerization reaction of the basethermoplastic polymer itself. For example, U.S. Pat. No. 4,617,374 toPruett et al. teaches such UV absorbers for polyester end-uses. Again,however, such compounds exhibit very high extraction results unless theyare added as to-be-polymerized reactants themselves with the estermonomers during the polymerization step. In such an instance, these UVabsorbers are actually integrated within the polymer, and not just mixedwithin the thermoplastic medium. As such, although such compounds doexhibit excellent results when polymerized within the target polyester,unfortunately such compounds are limited in their versatility since theonly time during which effective introduction is permitted is during theaforementioned polymerization procedure. There thus still remains a needto provide a more versatile UV absorber for thermoplastic end-uses suchthat the producer can introduce the UV absorber at any time during theproduction of the target thermoplastic such that the additive does notexhibit such high extraction and yet still provides excellent UVabsorbing properties thereto.

It has now been found that through the addition of polyoxyalkylenechains onto certain ultraviolet absorber compounds, greater versatilityof potential uses for the new UV absorber is provided, particularly interms of the needed low-extraction as noted above. Therefore, it hasbeen found that such polyoxyalkylenated compounds (such as those,without intending to limit the breadth of the invention, themethine-based compounds utilizing vanillin and resorcinol as startingmaterials) provide UV absorbers which are highly effective in filteringharmful UV-A and UV-B rays over a broad spectrum (λ_(max) from about 280to about 400 nm, more preferably from about 320 to about 400 nm).Furthermore, it has been found that in combination with a benzotriazoleand/or a hydroxybenzophenone, or other similar type of UV absorbercompound, the resultant composition is accorded protection from a greatamount of potentially damaging UV radiation (from approximately 250 toabout 400 nm). Additionally, such a combination is highly stable withinthe desired media, and thus provides long-term protection to the desiredsample stored within the target treated plastic article. Additionally,such compounds are very low in color when prepared in accordance withcertain procedures, most notably with certain alkoxylation catalysts,including, without limitation, metal hydroxides and other bases, bothalone and in the presence of amine-based alkoxylation catalysts(particularly with affinities for available protons), as well as rareearth phosphate salts, such as those taught within U.S. Pat. Nos.5,057,627, 5,057,628, 5,059,719, 5,118,870, 5,208,199. Such low-coloralternatives thus provide the basis for effective utilization withincolorless (clear and transparent) applications, such as the desiredclear plastics, while simultaneously providing the necessary effectiveUV protection.

Although some interest has been demonstrated within the area of certainmethine-based UV absorber compounds (i.e., L'Oreal's malonatederivatives), to date there has been no disclosure or fair suggestionregarding the utilization of the polyoxyalkylenated derivatives of suchUV absorbers in that capacity within certain media (such as, forexample, plastics), or on other surfaces (skin, textiles, for example),or in other applications (inks, and the like, for example). Inparticular, no disclosures exist concerning low-color, low-extraction(migration) polyoxyalkylenated UV absorber compounds that provideeffective protection from UV exposure between the wavelengths of fromabout 320 to about 400 nm. There is thus a great need within the UVabsorber market, and most particularly within the transparent plasticfilm and container markets (for storing and protecting food, pills, andthe like) for such types of improvements associated with relativelyinexpensive materials and processes provided by the inventivepolyoxyalkylenated methine-based UV absorber compounds.

Other ultraviolet absorbing compounds and compositions have beendeveloped or modified for certain plastic (thermoplastic, thermoset,etc.) applications, such as a class of compounds known by the name ofTinuvin®, available from Ciba, and noted above. Although such compoundsappear to provide very good ultraviolet protection both to the plasticitself and to any stored liquids, solids, etc., within a container madetherewith such plastics, unfortunately such a class of compoundsexhibits undesirable or problematic deficiencies. In particular, thebreadth of protection within the UV spectrum is generally limited tofrom about 320 to about 375 nm with such compounds. Thus, they generallydo not provide adequate UV protection to contents of plastic packagingover the entire range of UV wavelengths. Also, such Ciba compounds aregenerally naturally solid in nature and thus are either dispensed withintarget resins as solid powders or must be dispersed within liquids bythe end-user at time very close to dispensing in order to be effective.If any such Ciba UV absorbers are in fact liquid, they still are limitedin their breadth of UV protection in terms of wavelength ranges. Lastly,such Ciba compounds exhibit relatively high extraction levels andmigratory characteristics from within target plastic resins,particularly thermoplastics such as polyethylene terephthalates. Thus,although such compounds are effective for UV protection to a certainextent, there are a number of drawbacks for which improvements arehighly desired and necessary. To date, there thus remains a great needto provide an effective UV absorber that eliminates the above-noteddeficiencies.

OBJECTS OF THE INVENTION

It is therefore an object of this invention to provide novel low-color,low-thermoplastic-migrating (e.g., low-extraction), ultravioletabsorbing compounds, which may further be liquid when present in theirpure, undiluted states at room temperature and that provide UVprotection over a broad range of wavelengths up to at least 390 nm. Afurther objective of this invention is to provide a polymeric UVabsorber that can be used within various media and on differentsubstrates as an effective UV filtering compound or within a suitablecomposition for protection against potentially harmful ultraviolet rays.A further object of this invention is to provide a methine-based UVabsorber that provides bright and clear plastic articles. It is yetanother object of this invention to provide certain polyoxyalkylenatedmethine-based ultraviolet absorbers which do not require the presence ofan appreciable amount of bluing agent in order to provide alow-yellowing effect within clear thermoplastic applications (and thusprovides brighter clarity within the target plastic or other medium).Yet another object of the invention is to provide an effective UVabsorbing composition or article which comprises the inventivelow-color, low-thermoplastic-migrating ultraviolet absorbing compounds,particularly with wherein such compounds liquid in nature when undilutedat room temperature. Additionally, an object of this invention is toprovide a low-color UV absorber that provides protection to contentswithin clear thermoplastic packages such that degradation will notreadily occur due to exposure to UV wavelengths within the range of 250to 400 nm. Also, methods of producing such low-color UV absorbingcompounds are also provided.

DESCRIPTION OF THE INVENTION

Accordingly, the present invention thus encompasses a clearthermoplastic article having an average thickness of at most 35 milscomprising at least one ultraviolet absorber compound exhibitingultraviolet absorption characteristics over the range of wavelengthsfrom about 300 to about 400 nm such that said article exhibits a UVtransmission of at most 10% at the 390 nm wavelength; and wherein saidat least one compound exhibits an extraction level from saidthermoplastic article measured as the level of absorbance exhibited by aheated alcohol extract solution after 2 hours exposure of at most 0.1absorbance units in a cell with a 10.0 cm optical path length,preferably 0.05, more preferably 0.025, and most preferably as low as0.0; wherein said ultraviolet absorber comprises at least onepoly(oxyalkylene) chain of at least six total moles of oxyalkylene, oralternatively wherein said ultraviolet absorber is introduced withinsaid thermoplastic at any time during the production of said article, oralso alternatively, wherein said at least one ultraviolet absorber is aliquid prior to incorporation within said thermoplastic article and atroom temperature in its pure, undiluted state. Also considered part ofthis invention is the same clear thermoplastic article as above whereinsaid thermoplastic article simultaneously exhibits a yellowness level ofat most 2.5 and a brightness level of at least 90. Additionallyencompassed within this invention is a liquid ultraviolet absorbercompound exhibiting a Gardner color value of at most 11, wherein saidultraviolet absorber exhibits an extraction level from polyethyleneterephthalate measured as the level of absorbance exhibited by a heatedalcohol extract solution after 2 hours exposure of at most 0.1absorbance units, preferably 0.05, more preferably 0.025, and mostpreferably as low as 0.0. Further encompassed within this invention isan ultraviolet compound conforming to the structure represented byFormula (I)

wherein R₁, R₂, R₃, R₄, and R₅ are the same or different and areselected from the group consisting of C₁₋₂₀ alkyl, halo, hydroxyl,hydrogen, cyano, sulfonyl, sulfo, sulfato, aryl, nitro, carboxyl, C₁₋₂₀alkoxy, and B-A, wherein at least one of R₁, R₂, R₃, R₄, and R₅ is B-A,wherein B is selected from the group consisting of N, O, S, SO₂, SO₃,CO₂, and A is represented by the Formula (II)[polyoxyalkylene constituent]_(z)R′  (II)wherein polyoxyalkylene constituent is selected from the groupconsisting of at least three monomers of at least one C₂₋₂₀ alkyleneoxygroup, glydicol, glycidyl, or mixtures thereof, R′ is selected from thegroup consisting of hydrogen, C₁₋₂₀ alkoxy, C₁₋₂₀ alkyl, and C₁₋₂₀esters; wherein if B is N, then Z is 2, and if B is other than N, then Zis 1; X and Y are the same or different and are selected from the groupconsisting of hydrogen, cyano, C(O)OR, C(O)R, C(O)NR″R′″′, C₁₋₂₀alkyl,and C₁₋₂₀ alkoxy, or X and Y are combined to form a ring system, and R,R″, and R′″ are defined as above for any of R₁, R₂, R₃, R₄, and R₅; andwherein if X and Y are not combined to form a ring system then at leastone of said X and Y is either cyano or hydrogen. Another important partof this invention is thus a low-color ultraviolet absorbing compound aswell as a method of forming such a low-color ultraviolet absorbercompound wherein said ultraviolet absorber compound conforms tostructure represented by Formula (III)

wherein A is represented by the Formula (II)[polyoxyalkylene constituent]_(z)R′  (II)wherein polyoxyalkylene constituent is selected from the groupconsisting of at least three monomers of at least one C₂₋₂₀ alkyleneoxygroup, glycidol, glycidyl, and any mixtures thereof, and R′ is selectedfrom the group consisting of hydrogen, C₁₋₂₀ alkoxy, C₁₋₂₀ alkyl, andC₁₋₂₀ esters; wherein the method comprises the sequential steps of

a) reacting vanillin with at least one compound selected from the groupconsisting of at least one compound comprising at least oneoxyalkylene-containing group selected from the group consisting of atleast one C₂-C₂₀ alkylene oxide, glycidol, and any mixtures thereof, inthe presence of a catalyst; and

b) reacting the reaction product of step “a” with at least one alkylcyanoester (such as, without limitation ethyl cyanoacetate). Such anovel compound should exhibit a Gardner color level of at most 10 whenpresent within a methanol solution at a 5% concentration by volume and amaximum ultraviolet absorption within the range of wavelengths of 320and 400 nm, with a measured ultraviolet transmission of at most 10% ateach wavelength under 400 nm, preferably under 390 nm, when incorporatedat a loading of at most 0.5% by weight within a polyester article havinga thickness of at most 1 mm. Also, such a novel compound may also beliquid in its pure, undiluted state at room temperature, again tofacilitate handling and introduction within desired media, such as,without limitation, thermoplastics.

Also, this invention encompasses a method of forming a low-colorultraviolet absorber compound wherein said ultraviolet absorber compoundconforms to structure represented by Formula (IV)

wherein A is represented by the Formula (II)[polyoxyalkylene constituent]_(z)R′  (II)wherein polyoxyalkylene constituent is selected from the groupconsisting of at least three monomers of at least one C₂₋₂₀ alkyleneoxygroup, glycidol, glycidyl, and any mixtures thereof, and R′ is selectedfrom the group consisting of hydrogen, C₁₋₂₀ alkoxy, C₁₋₂₀ alkyl, andC₁₋₂₀ esters; said method comprising the sequential steps of

a) reacting resorcinol with a compound selected from the groupconsisting of at least one compound comprising at least oneoxyalkylene-containing group selected from the group consisting of atleast one C₂-C₂₀ alkylene oxide, glycidol, and any mixtures thereof, inthe presence of a catalyst to produce a polyalkoxylated resorcinol; and

b) reacting the reaction product of step “a” with a compound wherebysaid compound protects the polyalkoxylate hydroxyl groups;

c) converting the product of step “b” to an aromatic aldehyde throughthe production of a Vilsmeier complex;

d) subsequently reacting the aldehyde of step “c” with a basic substancewhich will liberate the polyalkoxylate hydroxyl groups; and

e) subsequently reacting the resultant product of step “d′ with an alkylcyanoester (such as, without limitation, ethyl cyanoacetate).

Such a novel compound, as that defined by structure (III), above, shouldexhibit a Gardner color level of at most about 11 when present within amethanol solution at a 5% concentration by volume and a maximumultraviolet absorption within the range of wavelengths of 320 and 400nm, with a measured ultraviolet transmission of at most 10% at eachwavelength under 400 nm, preferably under 390 nm, when incorporated at aloading of at most 0.5% by weight within a polyester article having athickness of at most 1 mm. Also, such a novel compound may also beliquid in its pure, undiluted state at room temperature, again tofacilitate handling and introduction within desired media, such as,without limitation, thermoplastics.

Compositions comprising such compounds of (III) and (IV) are alsoencompassed within this invention, particularly those comprising suchcompounds and bluing agents, as liquids or as pellets for furtherintroduction within desired molten thermoplastic formulations. Methodsof making such compositions, particularly thermoplastics, comprisingsuch compounds of (I), (III), and (IV) are also contemplated within thisinvention.

The term “thermoplastic” is intended to encompass any syntheticpolymeric material that exhibits a modification in physical state fromsolid to liquid upon exposure to sufficiently high temperatures. Mostnotable of the preferred thermoplastic types of materials arepolyolefins (i.e., polypropylene, polyethylene, and the like), polyester(i.e., polyethylene terephthalate, and the like), polyamides (i.e.,nylon-1,1, nylon-1,2, nylon-6 or nylon-6,6), polystyrenes,polyurethanes, polycarbonates, polyvinyl halides (i.e., polyvinylchloride and polyvinvyl difluoride, as merely examples), and the like.Preferred thermoplastics within this invention are polyesters, and mostpreferred is polyethylene terephthalate.

Such thermoplastic articles include bottles, storage containers, sheets,films, fibers, plaques, hoses, tubes, syringes, and the like. Includedwithin this list would be polyester, polystyrene and other like clearresinous materials in sheet form which are present within windows forstrength and resiliency functions. In such an instance, the low-color UVabsorbers of this invention would provide or contribute to excellent UVprotection for contents with target packaging articles (such as bottles,containers, and the like) or persons located indoors (such as withinhouses, buildings, cars, and the like, comprising windows with suchadditives included therein). Basically, the possible uses for such alow-color, low-migratory UV absorber is voluminous and cannot easily beenveloped. Other possible end-uses, however, would include solventsystems, printing inks, textile treatment compositions (either on orwithin textiles, fibers, fabrics, and the like).

Other types of articles contemplated within this invention for theparticularly disclosed clear UV protected thermoplastics include, againwithout limitation, films, sheets, bottles, containers, vials, and thelike. Ultraviolet absorbers are typically added to such compositionsduring the injection molding (or other type of molding, such as blowmolding), thereof, including, and without limitation, by mixing theliquid absorber with resin pellets and melting the entire coatedpellets, or through a masterbatch melting step while the resin andabsorber are pre-mixed and incorporated together in pellet form. Suchplastics include, again without limitation, polyolefins, polyesters,polyamides, polyurethanes, polycarbonates, and other well known resins,such as those disclosed within U.S. Pat. No. 4,640,690, to Baumgartneret al., and U.S. Pat. No. 4,507,407, to Kluger et al. under the term“thermoplastics”. Generally, such plastics, including the UV absorberadditive, are formed through any number of various extrusion, etc.,techniques, such as those disclosed in the aforementioned U.S. patents.Preferred thermoplastics are polyesters, such as, in one non-limitingembodiment, polyethylene terephthalate. “Plastic packaging” thusencompasses containers, sheets, blister packages, and the like, utilizedfor storage purposes and which include the plastics in any combinationas noted above.

The term “pure, undiluted state” as used in conjunction with the UVabsorbing compounds indicates that the compounds themselves without anyadditives are liquid at room temperature. Thus, there is no need to addsolvents, viscosity modifiers, and other like additives to the UVabsorbers to effectuate such a desirable physical state.

Such inventive polymeric UV absorbers, as noted above, are very low incolor [e.g., do not exhibit a b* value (indicating a degree of yellowingin this instance) above 2.5 on the CieLab scale]. Thus, there is no needto add appreciable amounts of other colorants (such as bluing agents,for example), acid scavengers, and other like additives, to theparticular UV absorber to provide such desired low-color (low-yellowing)characteristics. It should be well understood by one of ordinary skillin this art that such a benefit as low-yellowing without any otheradditives present applies solely to the particular compounds and doesnot indicate that any compositions comprising such compounds solelyinclude such inventive compounds as thermoplastic additives. In fact,other additives, such as the aforementioned bluing agents, acidscavengers, antistatic agents, optical brighteners, and the like, mayalso be added to these compounds prior to, during, and/or afterintroduction within the desired end product medium (such asthermoplastic, for example). The polymeric species may be determinedthrough destructive analysis (methanolysis, for example), and furtherspectrophotometric analysis thereof to locate any signatures of ananiline poly(oxyalkylene) comopund, as one example.

The term “solvent systems” encompasses any aqueous or organic liquidformulations. Non-limiting examples of the intended aqueous systemsinclude cleaning solutions, detergents, fabric softeners, marking inksand colorants, and keratin dyes. Non-limiting examples of organicformulations include the non-aqueous types of cleaning solutions,detergents, fabric softeners, marking inks and colorants, keratin dyes,as well as descalers, surfactant formulations, hydrocarbon compositions,and the like. The addition of inventive UV absorbers is accomplishedthrough the mere addition of the liquid compound within the targetsolvent system with simultaneous and thorough mixing.

Printing inks include compositions utilized as colorants within, again,as merely examples, pens, including, but not limited to ball-point andfountain pens, dot-matrix printers, toners for standard copy machines,ink-jet applications, permanent markers, dry-erase markers, newsprint,magazine print, laser jet printers, and the like. The addition ofinventive UV absorbers is accomplished through the mere addition of theliquid compound within the target printing ink formulations withsimultaneous and thorough mixing.

The term textile treatment compositions comprises both any formulationsfor application on textiles (and thus leaving at least a temporary UVabsorbing coating, or the like, on the textile surface). Incorporationof the inventive compounds within fibers of textiles is also encompassedwithin this term and thus within this invention. Skin protectant andskin tanning formulations basically encompass any compositionscomprising the novel UV absorbing compound which is utilized to protectskin from solar radiation.

The benefits accorded by the aforementioned novel ultraviolet absorbingcompounds are plentiful, considering the state of the art at this time.For example, clear thermoplastic or thermoset article are highlydesirable in order to facilitate recognition of compositions andformulations contained within such articles, for evident reasons. Foraesthetic purposes, such clear articles should not exhibit anydiscoloration. With most standard UV absorbers used today, yellowing isprevalent due to the inherent nature of the compounds themselvesproviding such color in order to absorb within the UV range. Thus, asnoted previously, bluing agents, in relatively high amounts, arerequired to counter this effect and provide the desired uncolored resin.The inventive plastics (and inventive compounds) do not exhibit suchdiscolorations to such a degree and thus, even though some yellowing maybe exhibited by such compounds, and thus within the targetthermoplastics, the use of much lower amounts of bluing agents providesthe needed clear, uncolored resin, thereby saving on cost and reducingthe work needed to provide such a proper clear article as well as abrighter article. Because bluing agents not only aid in preventingyellowness within target media, but also contribute grayness therein aswell, the utilization of large amounts of such agents is generallyavoided. The inventive compounds thus provide clarity with low graynesslevels due to the low-color aspects available therewith. As a result,the desired clear plastics exhibit heretofore unattained brightnesslevels with simultaneously extensive and effective ultravioletprotection over a wide range of wavelengths (as discussed above).Furthermore, such effective UV absorbing characteristics are noticeablein terms of protection for certain contents of target thermoplasticstorage articles. As discussed further below, such inventive UVabsorbers exhibit highly desirable ultraviolet absorptioncharacteristics over the range of wavelengths from about 300 to about400 nm such that an aqueous composition of riboflavin present withinsaid clear thermoplastic article will exhibit a degradation rate of atmost 75% after ultraviolet exposure over the wavelength range of 300 to400 nm after 20 hours of exposure to high intensity UV light (e.g., andfor all such experiments listed hereinafter, under at least 8 totalSylvania® 350 Blacklight bulbs, Model Number F40/350 BL, 40 watts each).

Furthermore, such inventive compounds exhibit extremely low migratory(e.g., low-extraction) levels from plastics and other media. Thepresence of poly(oxyalkylene) chains thereon provides a very versatileUV absorbing compound as a liquid or low viscosity additive that,exhibits thorough and effective mixing when introduced within the targetthermoplastic and following molding and cooling also exhibits very lowextraction levels therefrom. Such resultant low extraction levels areexhibited by said inventive compound (as well as said inventivethermoplastic) no matter when the inventive UV absorber compound isintroduced within the target thermoplastic during production thereof.Thus, introduction at the polymerization stage (as in Pruett et al.), aswell as at the injection molding stage, or even during the initialmixing stage of the target thermoplastic with its additives, all accorda very low-extraction result for the inventive UV absorbers. Suchversatility thus permits the user to set up his reaction method in termsof other limitations, rather than on the limits imposed by the effectiveintroduction of a low-extraction UV absorber compound (as now is thecase in Pruett et al.). Such a benefit thus accords the user theflexibility to introduce the necessary effective UV absorber at any timeduring thermoplastic production. Hence, introduction of such polymericcompounds within the target resins at any time during the productionmethod is facilitated by the liquid nature of most of the inventivepolymeric UV absorber compounds. Handling is greatly improved thereby,and more thorough dispersion within the desired medium is accomplishedas well. Again, costs are reduced due to simplicity and reliability isincreased with more thorough mixing, etc., through utilization of suchinventive compounds with simultaneous or concomitant reliability interms of performance and low extraction characteristics.

Additionally, such a highly reliable, easy-to-handle, low-color, andlow-migratory (low-extraction) UV absorbing compound also provides agreater range of protection than the standard UV absorbers now providedwithin the industry. Generally, such standard UV absorbers are effectiveup to about 380 nm, even with an increase in amount of such a compoundwithin the target medium (polyester, for example). Even with increasedamounts of such standard UV absorbers present within the target media(such as thermoplastics), the discolorations within the target mediumare more pronounced without a correlated benefit in a greater range ofprotected wavelengths. To the contrary, the inventive compounds provideprotection up to about 400 nm. This effect is easily shown through theselection of a certain chemical compound prevalent within stored liquidsand solids that is highly susceptible to UV attack and decomposition.For instance, as is shown in greater detail below, riboflavin (VitaminB₂) meets such a description; in comparison with standard UV absorbers(Tinuvin® 234, for example), the protection accorded riboflavin withinan aqueous solution and stored within a clear polyethylene terephthalatecontainer and exposed to a UV source between 320 and 400 nm for 20 hoursis significantly higher for the inventive vanillin- and resorcinol-basedcompounds. Such an improvement, in combination with any or all of theother characteristics exhibited by these inventive compounds, thus showsthe novelty and usefulness of such compounds, particularly within clear,and possibly plastic, applications.

In particular, such inventive UV absorbing compounds then conform to thefollowing structure (I)

wherein R₁, R₂, R₃, R₄, and R₅ are the same or different and areselected from the group consisting of C₁₋₂₀ alkyl, halo, hydroxyl,hydrogen, cyano, sulfonyl, sulfo, sulfato, aryl, nitro, carboxyl, C₁₋₂₀alkoxy, and B-A, wherein B is selected from the group consisting of N,O, S, SO₂, SO₃, and A is represented by A is represented by the Formula(II)[Alkyleneoxy constituent]_(z)R′  (II)wherein Alkyleneoxy constituent is selected from the group consisting ofC₂₋₂₀ alkyleneoxy, R′ is selected from the group consisting of hydrogen,C₁₋₂₀ alkoxy, C₁₋₂₀ alkyl, and C₁₋₂₀ esters; wherein if B is N, then Zis 2, and if B is other than N, then Z is 1; X and Y are the same ordifferent and are selected from the group consisting of hydrogen, cyano,C(O)OR, C(O)R, C₁₋₂₀alkyl, and C₁₋₂₀ alkoxy, and R is defined as abovefor any of R₁, R₂, R₃, R₄, and R₅; wherein at least one of R₁, R₂, R₃,R₄, and R₅ is B-A; and at least one of said X and Y is either cyano orhydrogen. Preferably, when X is an ester group, Y is cyano, B is O,Preferably, Alkylene constituent is either oxyethylene, oxypropylene, oroxybutylene, with oxyethylene and oxypropylene most preferred (between 2and 100 units of such monomers; preferably between 2 and 50; and mostpreferably, between 5 and 20); and R′ is preferably hydrogen. Suchcompounds thus must also exhibit the aforementioned low-color andlow-migration (from the target medium, such as plastic) characteristics,as well as existing as a liquid when in its undiluted state at roomtemperature.

Preferably, such a low-color ultraviolet absorbing compounds conform tothe structures represented by Formulae (I), (III), and (IV), above. Suchcompounds are poly(oxyalkylenated) in order to provide the desired lowextraction levels from thermoplastics as discussed above. The ability toprovide such low-color species for structures conforming to Formulae (I)and (III), above, and thus not resorcinol-based compounds, is apparentlycontrolled through the utilization of specific types of alkoxylationcatalysts, including, without limitation, rare earth salts (such aslanthanum phosphates), particular metal hydroxides (such as potassiumhydroxide both alone and in the presence of compounds having a strongaffinity for free and/or available protons within the reaction mediumitself, hereinafter referred to as “proton sponge”), and the like. Suchcatalysts, particularly the rare earth phosphates, apparently areconfigured in such a way that the levels of impurities and startingmaterials present within the reaction itself if drastically reduced incomparison with other standard alkoxylation catalysts (such as sodiumhydroxide) (although the true reasons behind such beneficial low-colorproduction is not completely understood). Preferred are lanthanumphosphate catalysts which are white powdery materials having a meanparticle size (D50) of between 5 and 50 microns, a lanthanum, content ofat least 58% by weight, and is substantially free from any chlorine. Thepoly(oxyalkylenated) products catalyzed therefrom exhibits much lesscolor in comparison with other standard alkoxylation catalysts (such asNaOH, as noted previously). Such a preferred catalyst is the sameutilized within the particular examples below.

Furthermore, without intending to be limited to any specific scientifictheory, it is postulated that such aforementioned proton spongecompounds prevent the potentially deleterious reaction of stronglycharged proton species from attacking the final reactants and reactionproducts and thus curtails the production of discoloring compoundswithin the final product itself. Examples of such proton spongecompounds include, without limitation, 1,8-bis(dimethylamino)naphthalene, 1,8-bis(diethylamino)-2,7-dimethoxynaphthalene,4,5-bis(dimethylamino)-fluorene, 4,5-bis(dimethylamino)phenanthrene,quino[7,8-n]quinoline, and the like, with1,8-bis(dimethylamino)naphthalene preferred.

Preferably, the alkoxylated compounds include either ethylene oxide orpropylene oxide, or mixtures of both, thereon having chain lengths from2 to about 100; more preferably such a chain length if from about 2 toabout 50; and most preferably such a chain length is from about 5 toabout 10, with all ethylene oxide also highly preferred. Thevanillin-based UV absorbing compounds of structure of Formula (III) arethus preferred embodiments of structure of Formula (I).

The structures conforming with Formula (IV) are also preferredembodiments of the structure of Formula (I)] are produced as low-colorpoly(oxyalkylenates) through the above-noted modified formylation of ahydroxyl-protected alkoxylated resorcinol through Vilsmeier complexationand subsequently deacetylating such a compound. In such an instance, theinitial alkoxylation may be performed through catalysis with moststandard alkoxylation catalysts. Again, the same types of oxyalkylenesand chain lengths thereof as noted above for the structures of Formulae(I) and (III) are preferred as well for the structure of Formula (IV).The starting material within the method of making such a compound isthus any resorcinol-based compound, preferably resorcinol itself. Afteralkoxylation, the resultant compound is reacted with a protectingcompound for the free hydroxyls thereon. Such a protecting compound maybe an ester anhydride, preferably at least one of C₁-C₂₀ esteranhydride, more preferably acetic anhydride. The protected compound isthen formylated with a Vilsmeier complex formed from, for example,N,N-dimethyl formamide and phosphorous oxychloride and can be anystandard compound of this type, including, without limitationdisubstituted formamides reacted with either phosphorous oxychloride,phosgene, or triflic acid, as merely examples. Of course, any otheraldehyde-forming group will function within this method in order toproduce an aromatic aldehyde based on the protected resorcinolpolyoxyalkylenated compound [such as resorcinol (6 moles of ethyleneoxide aka EO) diacetate]. In order to obtain a low color aldehydeproduct, the formylation reaction is run at a lower temperature (i.e.70° C. vs. 90° C.) and in the presence of hypophosphorous acid.Hypophosphorous acid is a well known reducing agent and it is believedthat its presence counters the formation of highly colored oxidizedspecies. The exclusion of oxygen during the reaction thus is highlycritical as well. After the aldehyde is formed, the protected hydroxylsare then liberated (e.g., deprotected) via base hydrolysis with anycompound or mixture of compounds having a pH level of at least 12, suchas NaOH, KOH, mixtures thereof, and the like. A mixture of the two basesis preferred.

Compositions comprising such compounds are also encompassed within thisinvention, particularly those of the compounds and bluing agents asliquids or as pellets. These broadly defined compounds as well as themore specific types thus provide the necessary characteristics for clearapplications (again, clear plastics, as one non-limiting example) interms of low color, low migration, liquid state, and effective andthorough mixing within the target medium.

The proper amounts utilized in the various compositions and applicationsare highly dependent on each of those separate possibilities. Thus, inplastics, for example, the inventive UV absorber is added in an amountof from about 0.001 to about 1.5% by weight of the total plasticcomposition, preferably from about 0.01 to about 1.0%, and mostpreferably from about 0.05 to about 0.5%. Such plastics may includeother standard additives, including antioxidants, clarifying agents,nucleators, acid scavengers, perfumes, colorants (for transparent, butcolored applications), antistatic agents, and the like.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The general methods of making and utilizing the preferred inventive UVabsorbers are as following:

Preparation of Compounds

EXAMPLE 1

Two thousand two hundred and eighty grams of vanillin, 20 g of lanthanumphosphate catalyst were charged to an autoclave. The autoclave was thensealed, purged several times with nitrogen gas (to a pressure of 60PSIG) and then pressurized to 5 PSIG of nitrogen. After heating theautoclave to 121° C., ethylene oxide was added to the reaction mixtureuntil a total of 3960 g were added over time. Once all of the ethyleneoxide was added, the mixture was post-cooked for a total of thirtyminutes. The mixture was then cooled to 93° C. and stripped at reducedpressure for fifteen minutes in order to remove un-reacted ethyleneoxide. The product is a pale yellow liquid with a hydroxyl number of134.

Nine hundred and thirty eight grams of4-polyoxyalkylene-3-methoxy-benzaldehyde from the reaction describedabove, 30 g of Vitamin E, 8 g of glycine, 150 g of water and 305 g ofethyl cyanoacetate were charged to a 5 liter three neck round bottomflask. In the presence of a nitrogen atmosphere, the mixture was heatedto 70° C. and held for three hours. Upon cooling to room temperature,2500 ml of water was added and the mixture heated to 75° C. Afterphasing, the product layer was washed again with 2500 ml of water.Removal of water via a rotovap yielded 862 g of product that has alambda max of 358 nm in methanol. Its color value in methanol, which isdefined as absorption per gram of sample in 1000 ml of methanol, is 41abs/g/l.

One thousand grams of such UV absorber was then mixed with 5 g ofClearTint® PC Violet 480 (a bluing agent) from Milliken & Company. TheUV blend was then used for the application testing.

EXAMPLE 2

Four hundred and fifty-six grams of vanillin, one gram of KOH flake andfour grams of proton sponge [1,8-bis(dimethylamino)naphthalene] werecharged to an autoclave. The autoclave was then sealed, purged severaltimes with nitrogen gas (to a pressure of 60 PSIG) and then pressurizedto 5 PSIG of nitrogen. After heating the autoclave to 121° C., ethyleneoxide was added to the reaction mixture until a total of 792 g wereadded over time. Once all of the ethylene oxide was added, the mixturewas post-cooked for a total of thirty minutes. The mixture was thencooled to 93° C. and stripped at reduced pressure for fifteen minutes inorder to remove un-reacted ethylene oxide. One thousand two hundred andfifty-three grams of product (yield 97%) is obtained as a pale yellowliquid with a hydroxyl number of 142.

100.4 grams of 4-polyoxyalkylene-3-methoxy-benzaldehyde from thereaction described above, 0.82 g of Vitamin E, 0.92 g of glycine, 20 gof water and 26.3 g of ethyl cyanoacetate were charged to a 250-ml threeneck round bottom flask. In the presence of a nitrogen atmosphere, themixture was heated to 70° C. and held for three hours. Upon cooling toroom temperature, 150 ml of water was added and the mixture heated to75° C. After phasing, the product layer was washed again with 150 ml ofwater. After the removal of water via a rotovap, the residue liquid wasdiluted with 200 ml of MeOH. The mixture was then filtered through a5-micron filter to yield 80 g of light yellow liquid product that has alambda max of 360 nm in methanol. Its color value in methanol, which isdefined as absorption per gram of sample in 1000 ml of methanol, is 42abs/g/l.

One thousand grams of such UV absorber was then mixed with 5 g ofClearTint® PC Violet 480 from Milliken & Company. The UV blend was thenused for the application testing.

EXAMPLE 3

One thousand eight hundred and thirty grams of 4-hydroxybenzaldehyde, 20g of lanthanum phosphate catalyst (as used above in EXAMPLE 1) werecharged to an autoclave. The autoclave was then sealed, purged severaltimes with nitrogen gas (to a pressure of 60 PSIG) and then pressurizedto 5 PSIG of nitrogen. After heating the autoclave to 121° C., ethyleneoxide was added to the reaction mixture until a total of 3960 g wereadded over time. Once all of the ethylene oxide was added, the mixturewas post-cooked for a total of thirty minutes. The mixture was thencooled to 93° C. and vacuum stripped for fifteen minutes in order toremove unreacted ethylene oxide. The product is a pale yellow liquidwith a hydroxyl number of 144.

Eight hundred sixty grams of 4-polyoxyalkylene-benzaldehyde from thereaction described above, 30 g of Vitamin E, 8 g of glycine, 150 g ofwater and 305 g of ethyl cyanoacetate were charged to a 5 liter threeneck round bottom flask. In the presence of a nitrogen atmosphere, themixture was heated to 70° C. and held for three hours. Upon cooling toroom temperature, 2500 ml of water were added and the mixture heated to75° C. After phasing, the product layer was washed again with 2500 ml ofwater. Removal of water via roto vap yielded 862 g of product that has alambda max of 338 nm in methanol.

EXAMPLE 4

Eight hundred grams of resorcinol, 400 g of toluene and 4 g of sodiumhydroxide pellets were charged to an autoclave. The autoclave was thensealed, purged several times with nitrogen gas (to a pressure of 60PSIG) and then pressurized to 5 PSIG of nitrogen. After heating theautoclave to 121° C., ethylene oxide was added to the reaction mixtureuntil a total of 1920 g were added over time. Once all of the ethyleneoxide was added, the mixture was post-cooked for a total of thirtyminutes. The mixture was then stripped at 100° C. via rotovap in orderto remove unreacted ethylene oxide and toluene (water was addedperiodically to aid in the removal of toluene). The final product had ahydroxyl number of 304.

Two hundred sixty six grams of polyoxyalkylene resorcinol from thereaction described above, 193 g of acetic anhydride and 2 g of N-methylimidazole were charged to a three neck one liter round bottom flask. Themixture was heated under a nitrogen atmosphere to 130° C. and held forthree hours. After cooling to room temperature, the mixture wastransferred to a 2 liter one neck round bottom flask and 200 g of waterwere added. The mixture was stripped at 100° C. via roto vap in order toremove the acetic acid byproduct. After removal of the acetic acid, 310g of polyoxyalkylene resorcinol diacetate remained.

To a five liter three neck flask, 915 g of N,N-dimethyl formamide wascharged. While under a nitrogen purge, 34 g of 50% hypophosphorous acidwas charged to the five liter flask. The resulting mixture was cooled to−5° C., at which 664 g of phosphorous oxychloride were added slowlywhile maintaining a temperature between −5 and 0° C. The resultingVilsmeier complex was added to a mixture (purged with nitrogen) of 1138g polyoxyalkylene resorcinol diacetate, 28 g of 50% hypophosphorous acidand 30 g of acetic anhydride. The temperature did not exceed 25° C.during the addition of the Vilsmeier complex. Once the addition wascomplete, the mixture was heated under a nitrogen atmosphere to 70° C.and held for two hours. Subsequently, the mixture was cooled to roomtemperature and added to a solution containing 2492 g of water and 1566g of 50% sodium hydroxide solution. This mixture was heated under anitrogen atmosphere to 75° C. and phased. The product layer was combinedwith 876 g of water, 546 g of 50% sodium hydroxide solution and 92 g of45% potassium hydroxide solution. While under a nitrogen atmosphere, themixture was heated to 70° C. and held for three hours. After cooling toroom temperature, 1000 g of water were added the mixture after it wasneutralized with 93% sulfuric acid solution to a pH of 7. The resultingmixture was heated under a nitrogen atmosphere to 75° C. and phased. Theproduct layer was stripped and passed through a filter leaving 880 g ofa pale yellow liquid. A 5% methanol solution of this liquid had aGardner color (1953 series) of 6. An IR spectra of this product shows apeak at 1670 cm (aldehyde carbonyl stretch). In methanol, this substancehas a lambda max of 273 run in addition to a second peak at 312 nm.

To a 500 ml three neck round bottom flask, 91 g of 2,4-polyoxyalkylenebenzaldehyde from the reaction described above, 3 g of Vitamin E, 0.85 gof glycine, 31 g of ethyl cyanoacetate and 20 g of water were charged.While under an atmosphere of nitrogen, the reaction mixture was heatedto 70° C. and held for three hours. After cooling the mixture to roomtemperature, 250 g of water were added and the mixture heated undernitrogen to 75° C. The phased product layer was washed again with 250 gof water. Upon stripping, 95 g of product remained. In methanol, thissubstance has a lambda max of 367 nm.

One thousand grams of such UV absorber was mixed with 8 g of ClearTint®PC Violet 480 from Milliken chemical. The UV blend was then used for theapplication testing.

COMPARATIVE EXAMPLE 1

Two thousand two hundred and eighty grams of vanillin, 20 g of sodiumhydroxide catalyst were charged to an autoclave. The autoclave was thensealed, purged several times with nitrogen gas (to a pressure of 60PSIG) and then pressurized to 5 PSIG of nitrogen. After heating theautoclave to 121° C., ethylene oxide was added to the reaction mixtureuntil a total of 3960 g were added over time. Once all of the ethyleneoxide was added, the mixture was post-cooked for a total of thirtyminutes. The mixture was then cooled to 93° C. and vacuum stripped forfifteen minutes in order to remove unreacted ethylene oxide. The productis an amber liquid with a hydroxyl number of 134.

Nine hundred and thirty eight grams of4-polyoxyalkylene-3-methoxy-benzaldehyde from the reaction describedabove, 30 g of Vitamin E, 8 g of glycine, 150 g of water and 305 g ofethyl cyanoacetate were charged to a 5 liter three neck round bottomflask. In the presence of a nitrogen atmosphere, the mixture was heatedto 70° C. and held for three hours. Upon cooling to room temperature,2500 ml of water were added and the mixture heated to 75° C. Afterphasing, the product layer was washed again with 2500 ml of water.Removal of water via roto vap yielded 862 g of product, which has alambda max of 358 nm in methanol. Its color value in methanol, which isdefined as absorption per gram of sample in 1000 ml of methanol, is 25abs/g/l.

COMPARATIVE EXAMPLE 2

To a 500 ml three neck flask, 135 g of N,N-dimethyl formamide wascharged and purged with nitrogen. Once cooled to −5° C., 99 g ofphosphorous oxychloride were added slowly while maintaining atemperature between −5 and 0° C. The resulting Vilsmeier complex wasadded to a mixture (purged with nitrogen) of 169 g polyoxyalkylene (6EO)resorcinol diacetate and 4.5 g of acetic anhydride. The temperature didnot exceed 25° C. during the addition of the Vilsmeier complex. Once theaddition was complete, the mixture was heated under a nitrogenatmosphere to 70° C. and held for two hours. Afterwards, the mixture wascooled to room temperature and added to a solution containing 369 g ofwater and 232 g of 50% sodium hydroxide solution. This mixture washeated under a nitrogen atmosphere to 75° C. and phased. The productlayer was combined with 153 g of water, 95 g of 50% sodium hydroxidesolution and 16 g of 45% potassium hydroxide solution. While under anitrogen atmosphere, the mixture was heated to 70° C. and held for threehours. After cooling to room temperature, 112 g of water were added themixture after it was neutralized with 93% sulfuric acid solution to a pHof 7. The resulting mixture was heated under a nitrogen atmosphere to75° C. and phased. The product layer was stripped and passed through afilter leaving 110 g of a light orange liquid. A 5% aqueous solution ofthis liquid had a Gardner color (1953 series) of 7.

COMPARATIVE EXAMPLE 3

To a 500 ml three neck flask, 135 g of N,N-dimethyl formamide wascharged and purged with nitrogen. Once cooled to −5° C., 99 g ofphosphorous oxychloride were added slowly while maintaining atemperature between −5 and 0° C. The resulting Vilsmeier complex wasadded to a mixture (purged with nitrogen) of 169 g polyoxyalkylene (6EO)resorcinol diacetate and 4.5 g of acetic anhydride. The temperature didnot exceed 25° C. during the addition of the Vilsmeier complex. Once theaddition was complete, the mixture was heated under a nitrogenatmosphere to 90° C. and held for two hours. Afterwards, the mixture wascooled to room temperature and added to a solution containing 369 g ofwater and 232 g of 50% sodium hydroxide solution. This mixture washeated under a nitrogen atmosphere to 75° C. and phased. The productlayer was combined with 153 g of water, 95 g of 50% sodium hydroxidesolution and 16 g of 45% potassium hydroxide solution. While under anitrogen atmosphere, the mixture was heated to 95° C. and held for threehours. After cooling to room temperature, 112 g of water were added themixture after it was neutralized with 93% sulfuric acid solution to a pHof 7. The resulting mixture was heated under a nitrogen atmosphere to75° C. and phased. The product layer was stripped and passed through afilter leaving 107 g of a dark reddish brown liquid. A 5% methanolsolution of this liquid exhibited a Gardner color (1953 series) of 13.

To a 100 ml three neck round bottom flask, 37 g of 2,4-polyoxyalkylenebenzaldehyde from the reaction described above, 3 g of Vitamin E, 0.5 gof glycine, 10 g of ethyl cyanoacetate and 10 g of water were charged.While under an atmosphere of nitrogen, the reaction mixture was heatedto 70° C. and held for three hours. After cooling the mixture to roomtemperature, 100 ml of water were added and the mixture heated undernitrogen to 75° C. The phased product layer was washed again with 100 mlof water. Upon stripping, 30 g of product remained. In methanol, thissubstance has a lambda max of 367 nm.

COMPARATIVE EXAMPLE 4

To a 500 ml three neck flask, 136 g of N,N-dimethyl formamide wascharged. While under a nitrogen purge, 5.2 g of 50% hypophosphorous acidwas charged to the 500 ml flask. The resulting mixture was cooled to −5°C., at which 99 g of phosphorous oxychloride were added slowly whilemaintaining a temperature between −5 and 0° C. The resulting vilsmeiercomplex was added to a mixture (purged with nitrogen) of 170 gpolyoxyalkylene (6EO) resorcinol diacetate, 4.2 g of 50% hypophosphorousacid and 4.5 g of acetic anhydride. The temperature did not exceed 25°C. during the addition of the Vilsmeier complex. Once the addition wascomplete, the mixture was heated under a nitrogen atmosphere to 90° C.and held for two hours. Subsequently, the mixture was cooled to roomtemperature and added to a solution containing 369 g of water and 233 gof 50% sodium hydroxide solution. This mixture was heated under anitrogen atmosphere to 75° C. and phased. The product layer was combinedwith 153 g of water, 95 g of 50% sodium hydroxide solution and 16 g of45% potassium hydroxide solution. While under a nitrogen atmosphere, themixture was heated to 95° C. and held for three hours. After cooling toroom temperature, 112 g of water were added the mixture after it wasneutralized with 93% sulfuric acid solution to a pH of 7. The resultingmixture was heated under a nitrogen atmosphere to 75° C. and phased. Theproduct layer was stripped and passed through a filter leaving 100 g ofa dark reddish brown liquid. A 5% methanol solution of this liquid had aGardner color (1953 series) of 11.

COMPARATIVE EXAMPLE 5

One thousand grams of p-formyl-N,N-polyoxyethyleneaniline (7 moles EO)were mixed with 124 parts of diethyl malonate and 30 parts of ammoniumcarbonate. The mixture was then heated between 70 and 75° C. for 10hours. The reaction was monitored by the UV-Vis spectra of the mixture.When the reaction was completed, as indicated by the presence of anabsorption maximum at 377 nm (A/gl=20.1), the product was then furtherstripped under reduced pressure to yield the final product.

COMPARATIVE EXAMPLE 6

Seventeen g of 3,4-dimethoxybenzaldehyde, 70 ml of toluene, 1 g ofpiperidine and 15 g of ethylcyanoacetate were charged to a 250 ml threeneck flask. In the presence of a nitrogen atmosphere, the mixture washeated to 110° C. and held for two hours. A precipitate formed oncooling. The precipitate was collected and recrystallized from 1:1toluene:acetone. After drying in an oven set at 70° C., a lightgreenish-yellow solid remained which has a lambda max of 357 nm inmethanol.

COMPARATIVE EXAMPLE 7

Seventeen g of 2,4-dimethoxybenzaldehyde, 70 ml of toluene, 1 g ofpiperidine and 15 g of ethylcyanoacetate were charged to a 250 ml threeneck flask. In the presence of a nitrogen atmosphere, the mixture washeated to 110° C. and held for two hours. A precipitate formed oncooling. The precipitate was collected and recrystallized from 1:1toluene:acetone. After drying in an oven set at 70° C., yellow needlesremained. A methanol solution containing this substance has a lambda maxof 368 nm.

COMPARATIVE EXAMPLES 8 AND 9 Synthesis of Vanillin UVA ModelCompound—Ethyl 2-Cyano-3(4-Hydroxy-3-methoxyphenyl)propenoate

EXAMPLE 8

Vanillin (15.2 g, 0.1 mol), ethyl cyanoacetate (12.5 g, 1.1 eq) andethanol (100 ml) were mixed in a 250-ml 3 neck round bottom flaskequipped with a reflux condenser. While stirring, piperidine (1.5 g) wasadded and the whole mixture was refluxed for 2 hours. After cooling downto RT, the mixture was acidified to pH 5-6 by 10% HCl. The precipitateformed was collected by filtration, washed several times with methanoland dried in air to result a bright yellow crystalline product (9 g)which had a absorption of 360 nm in acetone.

EXAMPLE 9

Vanillin (15.2 g, 0.1 mol), ethyl cyanoacetate (12.5 g, 1.1 eq) andtoluene (100 ml) were mixed in a 250-ml 3 neck round bottom flaskequipped with a reflux condenser. While stirring, piperidine (1.5 g) wasadded and the whole mixture was refluxed for 2 hours. After cooling downto RT, the mixture was acidified by a few drops of 10% HCl. Theprecipitate formed was collected by filtration, washed several timeswith methanol and dried in air to result a yellow crystalline product(19.2 g) which had a absorption of 360 nm in acetone.

Commercial samples of Tinuvin® 234 were obtained from Ciba. A samplebottle made with Eastman Heatwave® UV resin was obtained and tested forcomparative purposes as well. The sample was them introduced withincertain thermoplastic end-uses as for the other Comparative Examplesnoted above. The Ciba UV absorber was added as a powder within a moltenthermoplastic formulation and then mixed thoroughly therein.

Thermoplastic Composition Formation

The UV absorber was introduced within an injection molding operation fora polyester thermoplastic, for instance polyethylene terephthalate. Theliquid absorber was blended via agitation onto hot, dried polyethyleneterephthalate resin (in pellet form) in a chamber, which minimized theadsorption of moisture, by the resin. The blend of absorber and pelletswas gravity fed into the feed throat of the machine. In the feedsection, melting was accomplished though the utilization of a heated(heat transferred from the barrel of the machine) screw extruder whichrotated. The rotation of the screw provided thorough mixing of theabsorber and molten resin together producing a uniform plastic meltwhich was injected into a mold in order to form the intermediatethermoplastic article, for instance a parison.

The intermediate article (such as the parison) was allowed toequilibrate at normal room temperature and humidity before beingprocessed further. The article was positioned in front of a bank ofinfrared heaters that increased the temperature of the parison to itssoftening point. The heated parison was then transferred to a mold wherea rod was inserted into the parison stretching the end of the parison tothe bottom of the mold. Subsequently, pressurized air was blown into thestretched parison pushing the walls of the parison against the mold toform the desired thermoplastic article, such as a bottle, having anaverage thickness of about 15-20 mils.

Transmission Data for Polyester Resins

The percent transmission of UV light through 5 different PET bottle wallsections was measured on a Perkin-Elmer Lambda 35 UV-Vis Spectrometerwith a 50 mm Integrating Sphere. The wall thickness for all samples isaround 0.43 mm (17 mils). The UV transmission data is summarized intable 2.

TABLE 1 PET Bottles for UV Transmission Testing Bottle ID UV absorberloading and composition A (control) None B 1000 ppm Tinuvin ® 234(Comparative) C Eastman Commercial Bottle (Comparative) D 1000 ppmexample 4 E 1000 ppm of example 1 F 1000 ppm of example 4 and 1000 ppmof Tinuvin ® 234The transmittance spectra of the PET bottle wall sections were measuredfrom 250 nm to 450 nm in 5 nm increments. The results are as follows:

TABLE 2 % Transmission of UV Light through PET Resin Wavelength BottlesTested (nm) A B C D E 250 0.679 0.216 0.204 0.051 0.139 255 0.71 0.1660.142 0.013 0.128 260 0.721 0.136 0.078 −0.025 0.078 265 0.734 0.1360.174 −0.017 0.050 270 0.816 0.132 0.162 −0.133 0.058 275 0.835 0.122−0.002 −0.116 −0.077 280 0.843 −0.045 −0.155 −0.035 0.028 285 0.7340.122 −0.123 −0.104 −0.074 290 0.702 0.089 0.053 −0.092 −0.080 295 0.5550.039 0.011 −0.175 −0.054 300 0.549 −0.017 0.006 −0.122 −0.089 305 0.446−0.004 −0.025 −0.070 −0.119 310 0.656 0.068 −0.079 −0.150 −0.114 3150.851 0.013 0.050 −0.058 0.026 320 6.071 0.436 0.206 0.718 0.780 32537.58 2.617 0.220 5.514 3.692 330 57.683 3.501 −0.330 7.907 4.931 33564.309 3.159 −0.070 7.553 4.983 340 67.429 2.602 −0.069 5.948 4.161 34570.121 2.265 0.074 4.180 3.130 350 72.762 2.236 0.070 2.785 2.300 35574.583 2.500 0.041 1.868 1.728 360 76.104 3.261 0.095 1.328 1.368 36578.368 4.853 0.093 1.040 1.267 370 80.465 7.642 0.426 0.930 1.207 37581.829 12.652 2.074 0.916 1.317 380 82.801 21.659 8.993 1.215 1.659 38583.594 35.960 26.268 1.902 2.530 390 83.953 53.233 48.346 3.286 4.718395 84.433 67.935 64.050 6.169 9.771 400 84.896 77.356 72.800 12.86320.208 405 85.308 82.362 77.255 25.844 36.351 410 85.654 84.707 79.61043.944 53.844 415 85.932 85.863 81.020 61.386 67.699 420 86.149 86.46682.089 73.656 76.392 425 86.501 86.954 82.985 80.690 81.153 430 86.66487.217 83.691 84.044 83.497 435 86.892 87.409 84.207 85.562 84.681 44087.016 87.570 84.756 86.323 85.345 445 87.196 87.768 85.045 86.68385.748 450 87.310 87.868 85.351 86.891 85.981Since the lower % transmission represents better performance, it isevident that from a larger range of wavelengths, the inventive UVabsorbers provide greater overall protection for the target PET resin.The inventive UV absorbers provide much improved UV protection at longerwavelength range (between 370-390 nm). Furthermore, only the PET bottleswith the inventive UV absorbers can meet the specification oftransmission under 10% for wavelength below 390 nm.Protecting the Content from UV Damage

The main objective to incorporate UV absorber into PET packaging is toprotect the content from harmful UV damage. Such needs are more acute infood packaging. It is generally known that UV light would causedegradation of various nutrients, such as vitamins. It is now found thatthe inventive UV absorbers offer much improved protection against UVdamage relative to the commercial UV absorbers.

The vitamin B group has a wide and varied range of functions in thehuman body. Most B vitamins are involved in the process of convertingblood sugar into energy. Diets rich in B vitamins are particularlyimportant for pregnant and breast-feeding women and for other people whorequire more energy, such as athletes and heavy-labor workers. VitaminB₂, Riboflavin, is very important in the production of energy. VitaminB₂ can be found in milk, dried fortified cereals, and low fat yogurt.Deficiencies affect the skin and mucous membranes. Though riboflavin isquite stable to heat, it is very sensitive to light. It is particularlysensitive to ultraviolet light.

A study was conducted to determine the effectiveness of the PETpackaging to prevent the degradation of vitamin B₂ due to lightexposure. A stock solution of riboflavin was prepared by dissolving 50mg/L in deionized water. The stock solutions were protected from light.The PET bottles from previous experiment (listed in table 1) were used.The PET bottles were filled with the stock solution. The bottles wereplaced in a Q-Panel QUV Accelerated Weathering Tester with UVA-351bulbs. The choice of UVA light bulbs is to simulate the exposure tofluorescent light during warehouse, supermarket or other indoor storage.The degradation of the riboflavin was followed by monitoring theabsorption of the visible absorption peak at 444 nm. The control samplewas covered with aluminum foil and was subjected to the same treatment.The test data is summarized in table 3.

TABLE 3 % Residual Riboflavin after Light Exposure Light ExposureDuration (hours) Bottle ID 0 1 3 5 7 9 A 100% 100%  100%  100%  100% 100%  (foiled control) A (exposed) 100% 73% 25%  6%  3%  <1%   B 100%92% 77% 59% 44% 31% D 100% 95% 86% 72% 62% 50% E 100% 96% 85% 70% 60%48% F 100% 100%  89% 81% 73% 62%The data shows that the foiled control sample maintains the sameconcentration of riboflavin. Thus, the degradation is entirely caused bylight exposure. All PET bottles containing UV absorbers show much higherlevel of retained riboflavin than control. The bottles with theinventive UV absorbers show significant higher level of retainedriboflavin than the bottle with the best commercial product. Among allbottles, Bottle F shows the best protection of the content against lightexposure.Colorimetric Data for Polyester Resins

Although other UV absorbers with longer wavelength absorption have beendisclosed, they usually impart color within the polyester article. Formany of the packaging application, a colorless and transparent packageis essential. The inventive UV absorbers possess the exquisite balanceof imparting exceptional UV screening ability and no color to the PETarticles.

The Colorimetric data of the different PET bottle wall sections wasmeasured on a Gretag-Macbeth ColorEye 7000A Spectrophotometer. TheColorimetric data, using the CieLab scale, specifically L*, indicatingthe lightness/darkness, and b*, indicating yellowness/blueness of thePET bottle wall section are as follows:

TABLE 4 Colorimetric data of PET Resins UV absorber (from Table 1,above, with ppm) L* b* Example 4 (1000 ppm) 93.89 2.10 Example 1 (1000ppm) 93.79 2.22 Comparative Example 1 (1258 ppm) 95.51 6.25 ComparativeExample 3 (873 ppm) 95.33 5.61Thus, the comparative examples exhibit similar L* values (brightness)but with simultanouesly high yellowness (b* values). Measurements forthese values are preferably at least 90 for L* and at most about 2.5 forb* to signify a low yellowing resin with very low amounts of grayingbluing agents, and thus a very bright appearance. Attempts to reduce theb* value (e.g., yellowness) of the comparative UV absorbers involved theaddition of bluing agents which thus reduced the brightness (L*) of thetarget resins to values below the target value of 90.Colorimetric Data for Liquid UV Absorbers

As stated before, being colorless is very important for thisapplication. The inventive process can reduce the level of color withinthe inventive UV absorbers. In this experiment, the UV absorbers weredissolved in methanol to make up a 5% solution. The Gardner color wasmeasured. Data is shown in the table 5. A higher Gardner color indicatesthat the UV absorber is more likely to impart color within the final PETarticle.

TABLE 5 Gardner Color of UV Absorbers Sample (from Examples above)Gardner Color 1 10 4 11 Comparative Example 1 11 Comparative Example 318Thus, the data show that the inventive process significantly reduce thelevel of color within the inventive liquid UV absorbers.Extraction

Food packaging is one of the largest application that requires UVprotection within the packaging material. Therefore, exhibition ofnon-migration characteristics under normal use conditions is animportant requirement for the inventive colorless UV absorbers. Theirmigratory properties were studied by the following extraction test.

Polyester plaques containing the UV absorber additives were preparedusing standard compounding methods. Each plaque had a surface area of12.5 in². The PET plaques were made using ClearTuf® 8006 PET (from M&GPolymers) resin while the PEN plaques were prepared using PEN Hypertuf®(from M&G Polymers).

For each additive, the following extraction procedure was followed:

Solutions of 95% ethanol were used as food simulating solvent. USP 200proof absolute ethanol was diluted with DI water to prepare theextraction solvents. Stainless steel pressure vessels havingTeflon®-lined tops were used as extraction vessels in this study. 125 gof extracting solvent and 6 plaques/vessel were employed in thesestudies. The plaques were arranged so that the plaques were immersed andexposed on all sides to the extraction solvent.

Six plaques were cut in half and placed in a stainless steel extractionvessel and 125 g of 95% ethanol (preheated to 70° C.) was added. Thevessels were then sealed and placed in a 70° C. oven for 2 hours, atwhich time they were then removed. Subsequently, the plaques were thenremoved from the extraction vessels and the solvent was allowed to coolto ambient temperature. The extract solutions were then analyzedspectrophotometrically to determine if any UV absorbers had beenextracted from the target resins.

The extracts were analyzed spectrophotometrically to determine thepresence or absence of extracted colorant. A Beckman® DU 650spectrophotometer with a 10.00 cm path length cell was used. Theinstrument was first zeroed using the extract obtained from theuncolored polyester plaques. The extract from the extraction of theplaques containing the various additives was then scanned through theultraviolet/visible range to determine the presence or absence ofdetectable peaks at the additives' {circle around (2)}_(max) and thecorresponding absorbency. Higher absorption level at the additives'{circle around (2)}_(max) would indicate higher extraction level. Theterm “heated alcohol extraction test” as it pertains to this inventionencompasses such an analytical procedure as this in association withthis invention.

The results are summarized in the following table 6 and 7.

TABLE 6 Extraction Results in PET Sample UV absorber (from ExtractionResult Examples above) Loading (absorption at {circle around (2)}_(max))Comparative example 6 284 ppm 0.62 Comparative example 7 272 ppm 0.60Tinuvin ® 234 600 ppm 0.20 Comparative Example 8 200 ppm  0.172Comparative Example 9 200 ppm  0.179 Example 1 600 ppm 0.02 Example 2600 ppm Non-detectable

TABLE 7 Extraction Results in PEN Extraction Result Sample ID Loading(absorption at {circle around (2)}_(max)) Comparative example 6 284 ppm0.016 Comparative example 7 272 ppm 0.030 Tinuvin ® 234 600 ppm 0.003Example 1 600 ppm Non-detectable Example 2 600 ppm Non-detectableThus, the data shows that inventive UV absorbers show much reducedextraction level that that of the comparative examples and thecommercial UV absorbers. The inventive UV absorbers are more suitablefor food contact applications. In the case of Comparative Examples 8 and9, such results as noted above in Table 6 indicate that introduction ofsuch UV absorbers (from the Pruett et al. patent) during the injectionmolding stage, rather than during the actual polymerization stage of thetarget thermoplastic results in highly undesirable extractionmeasurements, particularly in comparison with the polymeric UV absorbersof the instant invention.

While specific features of the invention have been described, it will beunderstood, of course, that the invention is not limited to anyparticular configuration or practice since modification may well be madeand other embodiments of the principals of the invention will no doubtoccur to those skilled in the art to which the invention pertains.Therefore, it is contemplated by the appended claims to cover any suchmodifications that incorporate the features of the invention within thetrue meaning, spirit, and scope of such claims.

1. A liquid ultraviolet absorber compound exhibiting a Gardner colorvalue of at most 11, wherein said ultraviolet absorber exhibits anextraction level from polyethylene terephthalate measured as the levelof absorbance exhibited by a heated alcohol extract solution after 2hours exposure of at most 0.1 absorbance units within a cell having a10.0 cm optical path length.
 2. The liquid ultraviolet absorber of claim1 wherein said compound exhibits an extraction level of at most 0.05absorbance units.
 3. The liquid ultraviolet absorber of claim 2 whereinsaid compound exhibits an extraction level of at most 0.025 absorbanceunits.
 4. The liquid ultraviolet absorber of claim 3 wherein saidcompound exhibits an extraction level of 0.0 absorbance units.